2005 z71 occasional front end vibration

Hi there! My truck has been getting a vibration in the front end when it is at speeds from 50-70, sometimes fairly violently, and while slowing down it gets worse. After coming to a stop and checking to see if I have a bad tire, I turned around in parking lot to get back on the highway, and it was compleatly gone. I got the tires rotated and a wheel alighnment. Then 4 days go by, and it is still does the same thing. I can pull off the highway into a parking lot, stop, back up, and turn around get back on hwy, and then it is gone. Just looking for some info to see what direction to take. Also while getting the rotation and alingment, I checked the bearings/hubs. I told the tech what my truck was doing, and he said ball joints and tie rods were fine. So I was thinking CV joints/shafs or stering linkage....Thoughts?

Welcome to gmtc. I don't think that it would be the linkage. I had a similar issue with my 95. It turned out that the idler arm bracket bolts had loosened. How are the tires on the truck? I see that you had them rotated so that might eliminate a tire issue. If you put it in 4x4 on a dirt road do you get any really odd noises? If you take it up to 50mph in 4x4 is the vibration better/worse? Could be a cv shaft. But I would think that you would feel the vibration on the bad side, not the entire front end. Could also be font u joints. I would check them for play. It could also be a front diff issue. Driving it in 4x4 on dirt may help to pin point your issue.